Variable Hydraulic Pump Calibration via Valve Pressure Difference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydraulic pump calibration systems fail to accurately adapt pump characteristics to individual pumps, leading to variations in discharge flow rates.
Innovation Solution
A pump system with a hydraulic pump, regulator, pressure sensors, and a control device that calculates actual discharge flow rates based on pressure differences and opening degrees to create pump characteristics matching the command discharge flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pump characteristics are calibrated based on specified pump flow rates, then calibration can be performed for various current command values, but the pump characteristics cannot accurately adapt to actual pumps when the pump flow rate varies from pump to pump
Solution Approach 1:
The system measures the actual pump flow rate using a flow rate meter and feeds this information back to the control device. The control device then adjusts the pump characteristics based on this feedback, creating a closed-loop calibration system that adapts to the actual pump performance rather than relying on theoretical specifications.
Solution Approach 2:
The calibration system uses the pump's own actual flow rate measurements to automatically adjust and create its own pump characteristics. The control device performs self-calibration by comparing commanded flow rates with actually measured flow rates and adjusting the pump control table accordingly, eliminating the need for external manual calibration procedures.
2Adaptability or versatility
If the pump flow rate is allowed to vary to adapt to actual pumps, then individual pump characteristics can be obtained, but the discharge flow rate deviates from the command discharge flow rate
Solution Approach 1:
The system changes the pump control table parameters based on measured actual flow rates. By adjusting the relationship between current command values and actual flow rates, the system creates customized pump characteristics for each individual pump, transforming the pump control parameters to match actual pump behavior while maintaining precise flow rate control.
Solution Approach 2:
The system performs preliminary calibration measurements to determine the actual flow rate characteristics of each pump before normal operation. This preliminary action of measuring and storing the actual pump characteristics allows the pump to be pre-adjusted to its specific performance profile, ensuring accurate flow rate control from the start of operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system ensures accurate discharge of working fluid at the desired flow rate, adapting pump characteristics to actual pumps, thereby improving calibration accuracy.
Implementation Method 1
a first pressure sensor that measures upstream pressure that is hydraulic pressure of a working fluid flowing from the hydraulic pump to the opening degree control valve
Implementation Method 2
a second pressure sensor that measures downstream pressure that is hydraulic pressure of the working fluid flowing from the opening degree control valve
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This pump system includes: a hydraulic pump of the variable capacity type; a regulator; an opening degree control valve; a first pressure sensor; a second pressure sensor; and a control device. By changing a command signal to be output to the regulator, under a measurement condition in which the opening degree of the opening degree control valve is fixed at a predetermined opening degree, the control device causes the first pressure sensor and the second pressure sensor to detect upstream pressure and downstream pressure, respectively, with a plurality of command signals different from each other, calculates, for each command signal, an actual discharge flow rate of the working fluid discharged from the hydraulic pump, on the basis of the opening degree of the opening degree control valve and the pressure difference between pressure on the upstream side of the opening degree control valve and pressure on the downstream side of the opening degree control valve that is calculated on the basis of the upstream pressure and the downstream pressure detected, and creates pump characteristics so that a command discharge flow rate with respect to each command signal matches the actual discharge flow rate.